I do a version of a song I vaguely remembered from a movie years back, filled in what I couldn't remember with gibberish LOL
Squidgery didgery didgy didge, squidgery didgery doo...
I love you...
I love you in the morning, and in the afternoon,
I love you in the evening, and underneath the moon (WOOOO)
Squidgery didgery didgy didge, squidgery didgery doo...
I love you.

DS loves it

ETA: turns out it's an actual song and it's just the nonsense syllables that I changed LOL - but I call him my Squidgy anyway so it works for us